1. Field of the Invention
The present invention relates to methods and devices for performing multipoint tracking, and particularly, to a method of performing multipoint tracking and related device which incorporate dilation and erosion algorithms.
2. Description of the Prior Art
For many years, a keyboard and a mouse have been most widely adopted as input interface devices for a user to interact with a computer. Clicking, dragging, and scrolling functions are easily performed through use of the mouse, which allows the user to launch applications and activate menu items. The keyboard provides typing and shortcut key input methods for rapid entry of text and numerical data, as well as quick access to the applications and menu items.
Another type of input interface device commonly utilized as a replacement for the mouse is a touchpad. The touchpad may be utilized to detect contact with the touchpad by a stylus or a user's finger, and track movement and tapping of the stylus or finger to control operation of the computer. The touchpad has found widespread application in mobile computing devices such as notebook computers and PDAs.
FIG. 1 is a diagram of a multi-touch input detected by a touchpad device. Multi-touch technology is simultaneous tracking of multiple contacts 101-106 with the touchpad, and has been in development since 1982. However, application of the multi-touch technology to consumer devices, such as notebook computers and cell phones, has only recently begun gaining popularity. Typically, multi-touch input requires detection of the multiple contacts 101-106 in raw data 100, and may include use of a gradient image processing method for finding touch regions of the multiple contacts, which allows for calculation of number of the contacts and positions of the contacts. However, in the presence of noise, or when the touchpad has a malfunction, e.g. a damaged sensor row 110, one touch region may be detected as multiple touch regions, resulting in erroneous calculation of the number of contacts and the position of the one contact. For example, in FIG. 1, the touch regions 102 and 103 are both split by a dead row (indicated by an arrow) of the touchpad. Thus, the prior art may detect eight touch regions, instead of six, and the relative positions of the touch regions 102 and 103 will be inaccurate.